1. Field of the Invention
This invention relates to a lubricating apparatus of lubricating an outer ring of a follower bearing.
2. Background of the Invention
In the related art, such a type of a lubricating apparatus for a follower bearing is known from Patent Document 1, which is shown in FIG. 6.
A commonly-known lubricating apparatus D as illustrated in FIG. 6 comprises a casing C, a lubricating member L mounted in the casing C and a plate member P covering a side surface of the casing C.
After the lubricating member L is mounted in the casing C, the plate member P is secured to the casing C by screws. In the lubricating apparatus D shown in FIG. 6, the casing C and the plate member P are separate members.
Because the commonly-known lubricating apparatus D illustrated in FIG. 6 comprises the casing C and the plate member P that are separate members, the number of components of the lubricating apparatus D is increased and also the number of steps of assembling the same is increased. To address this disadvantage, a lubricating apparatus illustrated in FIGS. 3 and 4 has been developed, which comprises a casing C molded in one piece of a metal-made ring r and resin by use of a die.
A follower bearing B using the lubricating apparatus D has an outer ring 2 rotatably mounted on the peripheral of a support shaft 1. The support shaft 1 has an end with which a screw portion 1a is formed integrally. The screw portion 1a extends outward from the outer ring 2.
The follower bearing B is fitted in the casing C and supports a supported object M having a rotation-receiving surface on which the outer ring 2 is to rotate as shown in FIG. 5. Specifically, the screw portion 1a extends through a stationary member F and is locked by a nut tightened onto the projecting screw portion 1a. The follower bearing B secured to the stationary member F in this way is in contact with the supported object M, so that the follower bearing B rotates during the movement of the supported object M relative to the stationary member F so as to make full use of the bearing capability.
On the other hand, a shaft hole 4 is formed in the casing C which holds the lubricating member L for lubricating the outer ring 2. After the support shaft 1 of the follower bearing B is passed through the shaft hole 4, a bottom face 5 is opposite to the outer ring 2. A positioning recess 6 is formed in a central area of the bottom face 5 and extends parallel to the axis of the support shaft 1. The positioning recess 6 is formed in a mountain shape in cross section.
In the casing C side faces 7 are formed on opposite sides of the bottom face 5, and catch pawls 8 are formed on the respective side faces 7.
The lubricating member L, which includes a sintered resin member which is of a porous structure impregnated with a lubricant, is mounted in the casing C structured as described above. The lubricating member L used may be made by overheating and solidifying a mixture of a powder of a thermoplastic resin material such as polyethylene or polypropylene with a lubricating oil or a lubricating grease.
A pair of protrusions 9 keeping a predetermined distance from each other is formed on the face of the lubricating member L which will face the outer ring 2 after the lubricating member L is mounted in the casing C. The protrusions 9 are located parallel to the axis of the support shaft 1 and to make contact with the outer ring 2. The contact face of each protrusion 9 is formed in an arc shape. Such a contact of the arc faces of the protrusions 9 to the outer ring 2 provides lubrication to the outer ring 2, and also the lubricant adhering to the outer ring 2 at this time lubricates the rotation-receiving surface of the supported object M.
The lubricating member L has recesses 10 formed in the other face opposite to the face on which the protrusions 9 are formed such that the recesses 10 have the respective downward open ends as shown in FIG. 4. In addition, catch lugs 11 are formed outside the recesses 10 for engagement with the catch pawls 8.
The lubricating member L designed as described above is mounted in the casing C such that a leaf spring S is interposed between the lubricating member L and the bottom face 5. The leaf spring S has a mountain-like shape in cross section with a top 12 aligned with the positioning recess 6.
For mounting the lubricating member L in the casing C, the casing C is placed so that its bottom face 5 points downward as shown in FIG. 4. Then, the leaf spring S is set on the bottom face 5 while the top 12 of the leaf spring S is aligned with the positioning recess 6. With the leaf spring S held in place in the casing C, the lubricating member L is pressed into the casing C against a spring force of the leaf spring S, and then the catch lugs 11 are engaged with the catch pawls 8 of the casing C.
Then, a screw portion 1a of the support shaft 1 is passed through the shaft hole 4 of the casing C with the lubricating member L thus fitted therein. Then, the screw portion 1a is passed through the hole drilled in the stationary member F shown in FIG. 5 and then is secured through a spring washer by a nut.
Citation List
Patent Document 1 JP Patent No. 4278659
In the well-known follower bearing illustrated in FIGS. 3, 4, since the top 12 of the leaf spring S is simply placed on the positioning recess 6, the leaf spring S remains very unstable until the lubricating member L is mounted. For this reason, when the lubricating member L is mounted in the casing C, the top 12 of the leaf spring S may slide out of the positioning recess 6 in some cases. However, it is impossible to check a position of the mounted leaf spring S from the outside once the lubricating member L has been mounted in the casing C. Thus, if the leaf spring S deviates from the positioning recess 6 in the casing C, the follower bearing with the leaf spring S deviating is shipped. Alternatively, if the leaf spring S deviating from its correct position is forcibly fitted, the leaf spring S may possibly be deformed. In some cases, however, the follower bearing may be shipped without finding the deformation of the leaf spring.
If the deviation or deformation of the leaf spring S is not corrected, the balance will be lost between the pressing forces of the protrusions 9, provided on the lubricating member L, applied to the outer ring 2. This gives rise to a disadvantage that an offset load acts on the outer ring 2 and therefore the bearing capability is impaired.
Usually, one leaf spring S is mounted on the positioning recess 6. Inadvertently, however, two closely stacked leaf springs S may be possibly mounted on. Such mounting of the two closely stacked leaf springs S causes an increase in spring force to be higher than necessary. In this case, the bearing capability is also impaired. In addition, such mounting of the two closely stacked leaf springs S for each follower bearing means the use of a larger number of leaf springs than necessary, leading to a disadvantageous increase in cost.
When the casing C and the plate member P, which are illustrated in FIG. 6, are designed as separate components, even if the leaf spring S deviates from its correct position or it is deformed as described above, they can be recognized in the process of attaching the plate member P. However, when the casing C is structured as one piece, it is impossible to recognize the deviation or deformation of the leaf spring S.
In other words, the disadvantageous problems of the lubricating apparatus illustrated in FIGS. 3, 4 newly arise by structuring the casing C as one piece.